1. Field of the Invention
The present invention relates to liquid-discharging recording heads for performing printing by discharging liquid, and more particularly, to an inkjet recording head for performing recording by discharging ink.
2. Description of the Related Art
In recording heads mounted in inkjet recording heads, electrothermal transducers (heaters) and driving circuits and lines therefor are typically formed on a substrate using a semiconductor process technique, as disclosed in Japanese Patent Laid-Open No. 2005-138428.
In recent years, inkjet recording apparatuses have been required to have a higher image quality and a higher recording speed. For that purpose, in substrates for inkjet recording heads, there are demands to increase the mount density of heaters and logic sections, to increase the number of arrays of nozzles in response to the increase in number of ink colors, and to increase the length of the nozzle arrays in response to the increase in number of heaters themselves.
The length of the recording head can be increased by a method disclosed in Japanese Patent Laid-Open No. 7-276643 in which a long recording head is formed by arranging a plurality of substrates in a predetermined direction.
The size of droplets to be discharged has recently been reduced further. For example, heaters and nozzles for discharging small droplets of 3 pl or less are sometimes arranged on a substrate at a high density (e.g., 600 dpi or more). When the length of the recording head becomes more than or equal to 1 inch (e.g., 2 inches), a flow-path forming member (orifice plate) tends to be easily peeled off the substrate by the influence of stress therebetween. Further, since the substrate and a support member supporting the substrate generally have different coefficients of linear expansion, the above-described peeling easily occurs through a heating process during mounting.
When two substrates each having a length of about one inch are arranged to be used as a recording head having a length of two inches, the influence of stress is reduced compared to an integrated substrate having a length of two inches. Therefore, the risk of peeling is reduced, and the production yield is improved. As a result, it is possible to enhance reliability of the head, to reduce the cost, and to enhance reliability as the product.
However, in the above-described head in which a plurality of substrates are arranged, the support member and a TAB (Tape Automated Bonding) serving as mounted components become relatively large, and this increases the cost.
Therefore, to reduce the cost of a long recording head in which a plurality of substrates are arranged, it is important to minimize the size of mounted components.